The problem of the measurement of the thickness of the individual acoustically thin layers in multilayered structures has received consierable attention. In most cases, the difficulties of the measurements are due to the multiple reflection from the boundaries; bence the problem is usually solved in the frequency domain where the resonance structure of the frequency response is analyzed [1]. In the case of polymer structures the problem of the inversion of the ultrasonic data for the thickness of all layers is complicated by the high ultrasonic abosorption and weak reflection from the internal boundaries. The other difficulty is the curvature of the specimen affected by the measurement [2].
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